Mechanical musical instrument.



No. 676,03l. Patented June ll, l90l. C. L. DAVIS.

MECHANICAL MUSICAL INSTRUMENT.

(Application filed Apr. 28, 1900 (No Modei.)

y a Z 8 4 [/0 L77 w iBY :6 M

UNITED STATES PAT ENT OFFICE.

CHARLES L. DAVIS, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGN-MENTS, TO SAID DAVIS AND AUGUST HEUER, JR, OF SAME PLACE.

MECHANICAL MUSICAL INSTRUMENT.

SPECIFICATION forming part of Letters Patent N 0. 676,031, dated June 11, 1901. Application filed April 28,1900. Serial No. 13,912. (No model.)

To all whom it may concern.-

Be it known that I, CHARLES L. DAVIS, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Mechanical MusicalInstruments, (Case No. 2,) of which the following is afull, clear,concise, and exact description, reference being had to the accompanyingIO drawings, forming a part of this specification.

My invention relates to mechanical musical instruments, and inparticular to a variety thereof capable of playing a piano or likeinstrument and commonly known as a mechanical piano-player.

The invention relates especially to the pneumatic apparatus by which thepiano-key-actuating levers or fingers are operated as a result ofadmission of air into the trackerboard ports of the apparatus.

The principal object of my invention is to secure an exceedingly quick,accurate, and effective stroke of the key-actuating finger or lever andan instantaneous return movement of the same.

To the attainment of the foregoing and other desired ends my inventionconsists in matters hereinafter set forth.

In the accompanying drawings, Figure 1 is a view of a portion of anapparatus embodying my invention and of connections for operating thepiano-key thereby. Fig. 2 is a view, partlyin section and partly inelevation, of the pneumatic apparatus illustrated in Fig. 1 on a largerscale.

In Fig. 2 of the drawings I have shown a bank or set consisting of threepneumatics for operating three piano-keys. It will be understood thatthe three pneumatics shown are arranged in this way merely as a desiredarrangement for banking them together, so as to economize space, andthat behind them are other banks of three each to the number required tooperate the desired number of 5 piano-keys.

The apparatus for actuating each key involves a bellows A or otherpneumatic, having two chambers a and a and a swinging member actuated bythe difference in pressure in these chambers-in this case a leveroriiapl. Asapreferredarrangementthisleaf or flap 1 is arranged directlybetween the airchambers a and a, as shown in the figures.

In the way now best known to me for carrying out my invention I normallymaintain an equilibrium of pressure in the two chambers a and a,preferablya vacuum or partial vacuum of the same degree in bothchambers. The flap 1 then stands in a middle position, as shown by thetwo end pneumatics in Fig. 2. When the pneumatic is to be operated, theair-pressure is varied in one of its chambers or sides, so as to disturbor destroy the equilibrium normally existing in such chambers. In casethe equilibrium is maintained by a vacuous condition of the same degreein both chambers, I destroy such equilibrium by admitting air into oneof the chambers. In such case the flap will swing to one side, as shownby the position of the flap in the middle pneumatic in Fig. 2, it beingunderstood that air has been admitted to the left-hand chamber of thatpneumatic to cause its flap to swing to the right.

After the pneumatic has been operated by this destruction of theequilibrium in the two air-chambers such equilibrium is again restored.The flap 1 then returns to its middle position, and thereby restores thepneumatic to its normal condition. This resto- 8o ration of the flap toits normal position I believe to be due to the fact that when it isswung to one side the air-pressure from the outside is greater upon thestretched portion of the bellows material-that is to say, the left-handportion of the material in the middle pneumatic in Fig. 2than upon thecollapsed portion of the bellows material. This preponderance ofatmospheric pressure upon the stretched portion has a tendency to col-9o lapse that portion, and this eflfect is not countel-balanced by theatmospheric pressure upon the collapsed material of the other side ofthe bellows. The result is that the flap will be drawn in a direction torestore it to its middle position. Should it swing by the middleposition, a preponderance of atmospheric pressure will take place uponthe other bellows material and the flap will be returned a slight extentin an opposite direction. This vibration of the flap continues until itassumes a balanced condition in its middle portion. Whether this be thecorrect interpretation of the action of the pneumatic or not, it isnevertheless a fact that the flap 1 does automatically restore itself toits middle or normal position as soon as a condition of equilibrium isrestored in the two sides or chambers of the pneumatic. As a result ofthis arrangement I procure a pneumatic which is exceedingly quick andeffective in its action and which is instantaneously selfrestoring.

As an arrangement for maintaining an equilibrium of reduced pressurebetween the two chambers or sides of the pneumatics, I provide them withpassages 3 3 3, which extend from their right-hand sides or chambers a aa to the exhaust chamber or chest B, which is understood to be suitablyconnected with the bellows or other exhaust apparatus in the instrument.This exhaust chest or chamber B is suitably formed in a casing or box 2,which serves as a supporting structure for the pneumatics A A. The othersides a aof the pneumaticsA A arealso connected with the exhaust chamberor chest B by passages 4 4 4, likewise extending between the sides actof the pneumatics and said exhaust chamber or chest. From this it willbe obvious that both sides of the pneumatics are normally incommunication with the same exhaust chamber or chest, and that theytherefore both have the same degree of vacuum or partial vacuum. Air isadmitted into the sides a a of the pneumatics from suitable air chambersor trunks 5 5 5, likewise formed in the casing or box 2. Air is admittedinto the passages 4 4 4 by valves 6 6 6, controlling ports in thepassages 4 4 4 opening into the air-trunks 5 5 5. The ports of thepassages 4 4 4, which open into the exhaust chamber or chest B, are alsoprovided with valves 8 S 8, which, with the valves 6 6 6, are carried byvalve stems or spindles 9 9 9, arranged so that when the air-port of thepassage 4 is closed by its valve 6 the exhaust-port of that passage willbe opened by its valve 8, and vice versa. The valve-spindles 9 9 aresupported by supports or guides 7 7. By this arrangement it will be seenthat when one of the valve-spindles is in a lowered position thecorresponding passage 4 will be closed to the corresponding air-trunk 5and opened to the vacuum-chamber B, whereby an exhaust or vacuumcondition will be maintained in the side air-chamber a of thecorresponding pneumatic. This is the normal condition of the arrangementand is indicated by the positions of the valves and valve-spindles inthe two end pneumatics in Fig. 2. It will also be seen that when thevalve-spindle is in an elevated position the air-port of its passage 4is open to the corresponding airtrunk 5 and the vacuum-port of thatpassage is closed to the vacuum chamber or chest B, whereby air will beadmitted to the chamher a of that pneumatic. It will thus be seen tocomprise one arrangement or mechanism for maintaining an exhaust orvacuous equilibrium in the two chambers of each pneumatic and also foradmitting air into one of the same.

In the use of pneumatics of this kind in a mechanical piano-player orlike instrument I have shown as one arrangement for elevating thevalve-spindles 9 9 9 to operate the respective pneumatics diaphragms 1212 12, arranged at the ends of passages 10 1O 10, which communicate withthe interior of the tubes or pipes 11, which are understood to extend tothe various ports of the tracker-board. By such arrangement when air isadmitted to one of the tracker-board ports and the corresponding tube orpipe 11 the diaphragm 12 at the end of that tube or pipe will be forcedupwardly, so as to lift the valve-spindle resting upon it, and therebyadmit air into the passage 4 of the corresponding pneumatic.

The diaphgrams12 12 are provided with bleeders 14 14, through which theair can be exhausted from the passages 10 10 and tubes 11 11 when it isshut off from the corresponding tracker-board ports. At such times thediaphgrams 1:2 12 will collapse and allow the valve-spindles 9 9 todescend, whereupon the chambers to (t of the pneumatics will be againout off from the air-ducts and placed in communication with thevacuum-chamber. As illustrative of one arrangement which can be employedin the operation of the mechanical piano-player to play the piano I haveshown in Fig. 2 mechanism whereby the actuation of the pneumatic willoperate to strike the piano key O. This mechanism comprises a finger 15for striking a piano-key, a link 16 for operating the finger 15, abell-crank 17, having arms connected to the link 16, and a rod 18,having one end connected to the lower arm of the bell-crank 17 and theother end connected to the upper end of the flap 1. By such arrangementa movement of the flap or leaf 1 to the right will cause the rod 18 toswing the bell-crank 17, so as to elevate the link 16 and swing the rearend of the finger upwardly, and thereby cause its forward end to strikeand depress the piano-key 0.

It will be seen that the pneumatic herein illustrated is simple andinexpensive. It has shown itself to be exceedingly quick and effectivein its operation-so much so that by it the most difficult passages andtrills can be played when it is used in a mechanical pianoplayer.

It will be understood that this pneumatic can be used in various waysother than that herein shown. I do not, therefore, wish to limit myselfto its use in a mechanical pianoplayer.

What I claim as my invention is-- 1. The combination with adouble-chambered collapsible pneumatic, of means for varyin g thepneumatic pressure in one chamber of said pneumatic, and means formaintaining a uniform pressure in the other chamber, substantially asset forth.

2. The combination with a collapsible pneumatic or bellows having twochambers; of means for maintaining a pneumatic equilibrium in the twochambers; and means for varying the pneumatic pressure in one chamheronly so as to destroy the equilibrium between the two chambers.

3. The combination with a collapsible pneumatic or bellows having twochambers; of means for maintaining an exhaust or vacuous condition ofthe same degree in both chambers; and means for admitting and exhaustingair from one only of said chambers.

4. The combination with the bellows, having two chambers and with anexhaust-chest and an air-trunk; of a normally open passage establishingcommunication between one side or chamber of the bellows and theexhaustchest; another passage leading from the other side or chamber ofthe bellows and having ports opening into the air-trunk and theexhaust-chest; and valve mechanism for opening the air-port in thelast-mentioned passage, and simultaneously closing the exhaust-portthereof, and vice versa.

5. The combination with the bellows or pneumatic having two chambers,and with an air-trunk and an exhaust-chest; of a normally open passageestablishing communication between the exhaust-chest and one side orchamber of the bellows; another passage extending from the other side ofthe bellows and having ports opening into the air-trunk and theexhaust-chest; valve mechanism for controlling said ports, saidmechanism being arranged to normally close the port to the airtrunk andto open the port to the vacuumchamber; a tracker-board passage; meansfor operating said valve mechanism so as to open said port to theair-trunk and close the port to the vacuum-trunk upon the admission ofair into the tracker-board passage.

6. The combination with the collapsible pneumatic or bellows having twochambers, and the exhaust and air ducts or chambers, and also with thetracker-board and a passage leading therefrom to the pneumatic; of meansfor normally maintaining a corresponding exhaust condition in both sidesor chambers of the pneumatics; and means for admitting air into one sideor chamber thereof upon the admission of air into the trackerboardpassage, and for exhausting air from such side or chamber upon theclosure of such tracker-board passage.

7. The combination with the bellows or pneumatic having two chambers,and with the air-trunk and exhaust chest or chamber; of a normally openpassage establishing communication between one side or chamber of thebellows and the exhaust chest or chamber; another passage extending fromthe other side or chamber of the bellows and having ports openingrespectively into the airtrunk and exhaust chest or chamber; avalvespindle carrying a couple of valves which are arranged to open theexhaust-port and close the air-port of said passage, and vice versa; adiaphragm arranged to actuate the valvespindle; a tracker-board passageterminating at said diaphragm so that the admission of air to thetracker-board passage will actuate the diaphragm and thereby thevalve-spindle; and a bleeder-port in the diaphragm, substantially asdescribed.

8. The combination with the piano-key-actuating finger; of a collapsiblepneumatic having two sides or chambers, and also having a swingingmember; mechanism between said finger and swinging member, whereby theoperation of the latter will actuate the finger, the exhaust chambers orpassages; means for maintaining an exhaust condition in both sides orchambers of the bellows; a tracker-board and tracker-board passage; andmeans for admitting air into one side or chamber of the bellows uponadmission of air into the tracker-board passage, and for exhausting thesame therefrom upon the closure of the tracker-board passage.

9. The combination of a collapsible pneumatic having rigid side wallsand a swinging member arranged between said walls so as to divide thepneumatic into two chambers, the said swinging member being attached tothe collapsible material extending between the rigid side walls, meansfor varying the pneumatic pressure in one of the chambers formed by saidswinging member, and means for maintaining a uniform pressure in theother chamber, substantially as set forth.

In witness whereof I hereunto subscribe my name this 14th day of April,A. D. 1900.

CHARLES L. DAVIS.

\Vitnesses:

A. MILLER BELFIELD. CHARLES E. IIUBERT.

